Closes #5338

Root cause

linuxDialog.show() launched runQuestionDialog() — which calls gtk_dialog_run() — from a bare goroutine. GTK3 is not thread-safe; all GTK/GDK calls must run on the GLib main thread. Running them from an arbitrary OS thread is undefined behaviour and causes segfaults.

Commit 5dc3e21 (GTK4 support, PR #4958) replaced the correct InvokeAsync call with a bare go func(), breaking GTK3 users.

Fix

Replace go func() { ... }() with InvokeAsync(func() { ... }) in linuxDialog.show(). This matches the pattern already used by showAboutDialog in the same file, which was unchanged and works correctly.

The inner go func() for user button callbacks is preserved — those are not GTK calls and are correct to run on a goroutine.

-	go func() {
+	InvokeAsync(func() {
 		response := runQuestionDialog(pointer(parent), m.dialog)
 		if response >= 0 && response < len(m.dialog.Buttons) {
 			button := m.dialog.Buttons[response]
 			if button.Callback != nil {
 				go func() {
 					defer handlePanic()
 					button.Callback()
 				}()
 			}
 		}
-	}()
+	})

Testing

• Verified on Ubuntu 24.04 / GTK 3.24.41 / webkit2gtk 2.50.4
• go test ./v3/pkg/application/ — all 170+ tests pass
• Fixed binary (dialogs-basic example) builds cleanly with CGO_ENABLED=1

Summary by CodeRabbit

• Refactor
  • Improved dialog-response handling execution on Linux for better reliability.